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<title>Directed vs. Undirected Graphs</title>
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<div class="PageCaption">Directed vs. Undirected Graphs</div>

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NodeXL can handle both directed and undirected graphs.
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Directed graphs are used to model asymmetric relationships.  Each edge has a start point and an endpoint.  In NodeXL the start point is the vertex specified in the Vertex 1 column of the <a href="../WorkbookTour/Worksheets.htm">Edges worksheet</a> and the endpoint is the vertex specified in the Vertex 2 column.  <a name="Arrowheads">Arrowheads</a> are shown at the Vertex 2 end of each edge in the <a href="../WorkbookTour/GraphPane.htm">Graph Pane</a>.
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Undirected graphs are used to model symmetric relationships.  The edges in an undirected graph do not have start points or endpoints, and arrowheads are not shown in the Graph Pane.
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Apart from determining whether arrowheads are shown, the directedness of a graph affects the way some of NodeXL's <a href="../Analysis/GraphMetrics.htm">graph metrics</a> are calculated.
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To specify whether a graph is directed or undirected:
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    In the Excel Ribbon, set NodeXL, Graph, Type to Directed or Undirected.
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